Caffeine, rather than E.coli, could be used as a marker for the contamination of water supplies, new research suggests.
A team from the University of Montreal's Department of Chemistry collected water samples from streams, brooks and storm sewer outfall pipes and analysed the samples for caffeine, faecal coliforms and carbamazepine, a regularly prescribed psychiatric treatment.
Professor Sebastien Sauve said: "E.coli bacteria is commonly used to evaluate and regulate the levels of faecal pollution of our water from storm water discharge, but because storm sewers systems collect surface runoff, non-human sources can contribute significantly to the levels that are observed."
As carbamazepine degrades very slowly, the team hoped it could be a useful indicator, but no correlation was found with the substance and contamination, unlike caffeine.
Once in the system, the team estimates caffeine takes between a few weeks and three months to degrade, making it a good candidate for an indicator. It is also consumed widely and has a strong association with domestic waste, rather than agricultural or industrial waste.
"This data reveals that any water sample containing more than the equivalent of ten cups of coffee diluted in an Olympic-size swimming pool is definitely contaminated with faecal coliforms.
"A caffeine sampling program would be relatively easy to implement and might provide a useful tool to identify sanitary contamination sources and help reduce surface water contamination within an urban watershed," Professor Sauve added.
Elsewhere, a University of Tennessee microbiologist is currently looking to develop a biofilter which will cleanse freshwater of the toxic algae which makes lakes and ponds unsuitable for human consumption.
The research targets the toxin microcystin, which is associated with liver damage in humans, and the team hope to isolate a number of bacteria which will consume the toxin and will ultimately be of use as a biofilter.